Hydraulic unit for traction-controlled motor vehicle brake systems

ABSTRACT

An electromagnetically actuated valve of a hydraulic unit is received in pressure-tight fashion and mounted without complicated adjustment of the valve stroke. The valve comprises a hydraulic part and an electrical part. The hydraulic part is a pre-mounted unit with a stroke of a seat valve set before insertion into a receiving bore of a metal valve block. The hydraulic part is received in pressure-tight fashion in the valve block by a first swaged connection located between an inlet conduit and an outlet conduit of the receiving bore. A sealing ring that closes off the receiving bore is retained by a radially extending flange of a bushing slipped onto the hydraulic part. The flange is secured to the valve block by a second swaged connection. The hydraulic unit is usable for traction-controlled motor vehicle brake systems.

BACKGROUND OF THE INVENTION

The invention is based on a hydraulic unit for slip-controlled motorvehicle brake systems.

One such hydraulic unit is already known (DE 42 02 389 A1), in which theelectromagnetically actuated valve is mounted in the valve block as asubassembly comprising a hydraulic and an electric part. The valve blockhas a deep, sharply stepped receiving bore, into whose bottom,small-diameter portion an inlet conduit and an outlet conduit open out.The hydraulic part of the valve, forming a pre-mounted unit engagingthis portion of the bore, has two sealing rings on the circumference ofits sleeve that receives a valve body, a magnet armature and a magnetcore; of the sealing rings, one is disposed between the conduits and theother is disposed toward the boundary plane of the valve block and isaxially supported by the electrical part of the valve. For that purpose,the electrical part engages a large-diameter portion of the receivingbore, on the side toward the boundary plane, and is retained in thisbore by a positive connection by means of a retaining ring press-fittedinto an undercut of the bore. In this known embodiment, the pressurefluid forces acting on the hydraulic part must be absorbed by theelectrical portion and transmitted to the valve block by the positiveconnection. The electrical part is therefore exposed to relatively majorforces. Moreover, the embodiment of this connection is expensive andrequires a large amount of space.

A space-saving way that is more favorable in terms of force dissipationto fasten an electromagnet valve and a valve block of a hydraulic unitfor traction-controlled brake systems is known from DE-40 30 571 A1.There, the valve comprises a hydraulic part and an electrical partmounted on it. The hydraulic part is not a premounted unit. Instead, itis made up of individual parts installed on the valve block; that is,first a valve body with a valve seat is inserted into a steppedreceiving bore and secured by means of a swaged connection. A guide diskfor a valve needle is inserted into the bore after that and secured.Near the boundary plane of the valve block, a bushing is then insertedinto the receiving bore. The bushing serves to receive a valve sleeve,widened in funnellike fashion on its end, which receives a magnetarmature and a magnet core. The valve sleeve is secured in the valveblock by a swaged connection, in which material positively displacedfrom the edge of the receiving bore covers the funnellike sleeve portionsupported by the bushing. This swaged connection is heavily loadedhydraulically and requires absolute tightness. It can therefore beachieved only in a valve block made of steel (see DE 38 10 581 A1).Adjusting the valve stroke is made substantially more difficult in thisembodiment, however, because the valve stroke is to a great extentdependent on the tolerances of the aforementioned individual parts ofthe hydraulic part, the tolerances of the receiving bore, and thequality of the swaged connections. Defects in the hydraulic part of thevalve that occur after the swaged connections have been made are nolonger repairable.

ADVANTAGES OF THE INVENTION

The hydraulic unit according to the invention has the advantage over theprior art that securing of the hydraulic part is done by means of thefirst swaged connection in a region remote from the mouth of thereceiving bore, which reduces the demands made on the material of thevalve block and on the swaged connection, so that instead of steel,ductile light metal, for instance, can also be used. Sealing off of thereceiving bore from the outside is now done instead by the sealing ring,placed against the boundary plane of the valve block. The load on it byhydraulic forces is advantageously absorbed by the flange secured to thesecond swaged connection. One quite essential advantage, however, is theuse of the hydraulic part as a premounted unit, because it is notsubject to any alteration of the preset valve stroke in the course ofthe joining process in the valve block, which can also be done in only afew work steps. The hydraulic unit can thus be made economically andwith high quality.

By means of the provisions recited, advantageous further developments ofand improvements to the hydraulic unit recited herein are possible.

An especially advantageous provision is the inclusion of the sleeve ofthe hydraulic part in the first swaged connection, in that the sleeve issurrounded in the annular groove by displaced material of the valveblock and is pressed intimately against the valve body. The load-bearingcapacity of the sleeve for hydraulic forces is increased considerablythereby. Moreover, sealing of the hydraulic part between the sleeve andthe valve body is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are shown in simplified form inthe drawings and described in further detail in the ensuing description.FIG. 1 is a longitudinal section through an electromagneticallyactuatable valve which is secured by swaged connections in the valveblock of a hydraulic unit for traction-controlled motor vehicle brakesystems; FIG. 2 shows a first exemplary embodiment of a connectionbetween the sleeve and a valve body of the hydraulic part of the valvebefore the swaged connection is made, and FIG. 3 shows this after theswaged connection has been made; FIG. 4 shows a second embodiment of theaforementioned connection after the swaging; and FIG. 5 shows a thirdembodiment of this connection prior to the swaging operation.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

An electromagnetically actuated valve 10 shown in FIG. 1 is disposed ona valve block 11 and forms part of a hydraulic unit 12, not otherwiseshown, for traction-controlled brake systems in motor vehicles. Thevalve 10 comprises a hydraulic part 13 and an electrical part 14. Thehydraulic part 13 is substantially received and secured in a steppedreceiving bore 15 of the valve block 11, which is of a ductile aluminumalloy. In the extension of the receiving bore 15, the hydraulic part 13protrudes with a valve dome 16 beyond a boundary plane 17 of the valveblock 11. The electrical part 14 is mounted on the valve dome 16.

The hydraulic part 13 has a thin-walled, tubular sleeve 19 ofcircular-annular cross section. Beginning at the receiving bore 15, thesleeve 19 receives a valve body 20 with a press fit. The valve body 20has a valve seat 21 for a closing member 22 of a magnet armature 23 thatis longitudinally movable in the sleeve 19. On the end remote from thevalve body 20, the sleeve 19 is closed off by a magnet core 24, as partof the valve dome 16. Leaving an air gap 25 from the magnet armature 23,the magnet core 24 engages the sleeve 19 with a press fit and is joinedto it by a weld seam 26 extending around it. This connection is pressuretight. A closing spring 27 engaging the magnet core 24 is received inthe magnet armature 23 and in the position of repose of the valve 10 asshown keeps the closing member 22 in contact with the valve seat 21: thevalve 10 is thus closed when the electromagnet is without current.

The hydraulic part 13 is a premounted unit with a stroke of the seatvalve 28, formed by the valve seat 21 and the closing member 22, that isset before insertion into the receiving bore 15. This seat valvecommunicates on the one hand with an inlet conduit 29 and on the otherwith an outlet conduit 30 in the portion of the receiving bore 15 remotefrom the mouth. The hydraulic part 13 is received in pressure-tightfashion in the valve block 11 by a first swaged connection 31 locatedbetween the inlet conduit 29 and the outlet conduit 30. This swagedconnection, which represents a positive engagement with the valve block11, is described hereinafter in conjunction with other exemplaryembodiments.

From the direction of the valve dome 16, a filter sleeve 34 associatedwith the inlet conduit 29, a sealing ring 35, and a support ring 36 areslipped onto the sleeve 19 of the hydraulic part 13. The receiving bore15 is sealed off in pressure-tight fashion from the boundary plane 17 bythe sealing ring 35 surrounding the hydraulic part 13. To that end, abushing 37 is slipped from the valve dome 16 onto the hydraulic part 13of the valve 10; its relatively thick tube wall 38 surrounds the sleeve19 with slight radial play in the region of the magnet armature 23. Onits side toward the support ring 36, the bushing 37 has a radiallyextending flange 39. This flange 39 is supported in the receiving bore15 on a bore step 40 and is joined to the valve block 11 by a secondswaged connection 41. This second swaged connection 41 is attained bycaulking of deforming the edge toward the mouth of the receiving bore15, at which displaced material of the valve block 11, taking the formof a bead 42, covers the flange 39 toward the mouth. This positivelyengaged connection is capable of absorbing hydraulic forces bearing onthe sealing ring 35 and diverting them to the valve block 11.

The electrical part 14 of the valve 10 is mounted, after the bushing 37is secured in the valve block 11, onto the valve dome 16 in the regionof the magnetically active elements, the magnet armature 23 and themagnet core 24. The electrical part 14 has an electrical coil 45, whichsurrounds the valve dome 16 essentially toward the magnet core. The coil15 is engaged on the outside by a housing 46 of soft magnetic material,into which an annular disk 47, likewise of soft magnetic material, ispress-fitted at the bottom. On the face end of the housing 46 remotefrom the boundary plane 17, connection pins 48 of the coil 45 areformed. The housing 46 of the electrical part 14, preferably withoutplay, surrounds the magnet core 24 on the one hand and on the other,with its annular disk 47 surrounds, the tube wall 38 toward the magnetarmature of the bushing 37. On excitation of the electrical coil 45, thebushing 37, like the magnet core 24, the housing 46, and the annulardisk 47, helps conduct the magnetic flux to the magnet armature 23 ofthe hydraulic part 13. The magnetically operative magnet core 24 shiftsthe magnet armature 23 to the open position of the valve 10.

The first swaged connection 31 serving to secure the hydraulic part 13of the valve 10 in the valve block 11 is embodied as follows (see FIG.2): the valve body 20 of the seat valve 28 takes the form of a straightcircular cylinder. With the predominant portion of its length, it isreceived with a press fit in the sleeve 19 of the hydraulic part 13. Thevalve body 20, in its middle portion, has an annular groove 51 oftriangular cross section. The terminal portion 52 of the sleeve 19 ispressed, along the entire groove circumference, against the groove wall53 of the annular groove toward the magnet armature by crimping. Theportion of the valve body 20 not encompassed by the sleeve 19 engages,with slight play, a portion 54 of the receiving bore 15 toward theoutlet conduit. This portion 54 of the bore terminates at anencompassing edge 55 of the receiving bore 15. After that, the receivingbore 15 widens to an extent that slightly exceeds the outer diameter ofthe sleeve 19. In its further course, the receiving bore 15 is widenedtoward the boundary plane 17 to a portion 57 of relatively largediameter, forming a bore step 56. This portion 57 provides space for adeforming tool 58 that surrounds the hydraulic part 13 with slight play;of this tool, only the portion toward the bore is shown in FIGS. 2-5.

The encompassing edge 55 of the receiving bore 15 forms a stop thatlimits the insertion depth of the hydraulic part 13 in the valve block11; the portion 52 of the sleeve 19 is crimped into the annular groove51 and engages this stop before the first swaged connection 31 is made.This swaged connection 31 is made by lowering the deforming tool 58, insuch a way that after striking the bore step 56 that greatly widens thereceiving bore 15, the tool displaces material of the valve block 11into the annular groove 51. As FIG. 3 clearly shows, the displacedmaterial fills up the annular groove 51, and along with the positiveengagement attained by the crimping of the sleeve portion 52 it alsobrings about a nonpositive engagement between the sleeve 19 and thevalve body 20, which reinforces the tightness and strength of the firstswaged connection 31. After the first swaged connection 31 is made, thedeforming tool 58 releases the hydraulic part 13 of the valve 10, sothat the mounting of the individual parts, mentioned above, of the valvein the receiving bore 15 can be done.

In a departure from this embodiment of the first swaged connection 31,the sleeve 19 may be lengthened axially beyond the annular groove 51. Inthat case, a positive engagement of the sleeve 19 with the valve body 20is attainable by beading in of the sleeve into the annular groove 51. Asa result, the sleeve 19 is pressed positively against both walls of theannular groove 51. If the encompassing edge 55 is to be used as a stop,then in this embodiment the portion of the valve body 20 after theannular groove 51, toward the magnet armature, must be embodied smallerin diameter, as is shown for the exemplary embodiment of FIG. 4.

The exemplary embodiment shown in FIG. 4 is distinguished in that thesleeve 19 terminates on its face end at a distance before the annulargroove 51 of the valve body 20. The valve body 20 is provided after theannular groove 51 with a shoulder 59 that reduces its diameter. As aresult, it is attained that the wall 53 of the annular groove 51 towardthe sleeve and having the larger diameter, before the first swagedconnection 31 is made, engages a stop formed by the encompassing edge 55of the receiving bore 15 and limiting the insertion depth of thehydraulic part 13 into the valve block 11, as is suggested by adot-dashed line in the region of the annular groove, as in FIG. 2. FIG.4 shows the status after the deforming operation has been concluded, bymeans of which material of the valve block 11 has been displaced intothe annular groove 51 located in the region of the shoulder 56 of thevalve body 20.

The exemplary embodiment of FIG. 5 shows the status before the caulkingoperation. Here, as in the exemplary embodiment of FIG. 4, the valvebody 20 is provided with a diameter-reducing shoulder 59. The annulargroove 51 is again located in the region of the shoulder 59. The valvebody 20 is also nonpositively surrounded by the sleeve 19 over only aportion of its length. Between the annular groove 51 and the sleeve 19,the valve body 20 has an encompassing shoulder 60 that reduces itsdiameter to the outer diameter of the sleeve. The purpose of thisshoulder is, when the swaged connection 31 is made, to reinforce theflow of material, displaced by the shoulder 56 of the receiving bore 15,from the valve block 11 into the annular groove 51.

The foregoing relates to preferred exemplary embodiments of theinvention, it being understood that other variants and embodimentsthereof are possible within the spirit and scope of the invention, thelatter being defined by the appended claims.

What is claimed is:
 1. A hydraulic unit (12) for traction-controlledbrake systems of motor vehicles,having the following characteristics: atleast one electromagnetically actuated valve (10) is disposed on a metalvalve block (11), the valve (10) has a hydraulic part (13), received ina stepped receiving bore (15) of the valve block (11), and an electricalpart (14), which is mounted on a valve dome (16) of the hydraulic part(13), said dome fits over a boundary plane (17) of the valve block (11),the hydraulic part (13) has a tubular sleeve (19), in which, beginningat the receiving bore (15), a secured valve body (20) with a valve seat(21), a longitudinally movable magnet armature (23) with a valve closingmember (24), and a likewise secured magnet core (24) are received, thehydraulic part (13) is a premounted unit with a stroke, set before theinsertion into the receiving bore (15), of the seat valve (28) formed bythe valve seat (21) and the valve closing member (22), the seat valve(28) communicates with an inlet conduit (29) and with an outlet conduit(30) of the receiving bore (15), the receiving bore (15) is sealed offfrom the boundary plane (17) by a sealing ring (35) surrounding thehydraulic part (13), the hydraulic part (13) is joined at leastindirectly by positive engagement to the valve block (11), the hydraulicpart (13) is received in a pressure-tight fashion in the valve block(11) by means of a first swaged connection (31) located between theinlet conduit (29) and the outlet conduit (30); the receiving bore (15)is closed off between the sealing ring (35) and the boundary plane (17)by a radially extending flange (39) of a bushing (37) that is slippedonto the hydraulic part (13); the flange (39) of the bushing (37) isbraced against a bore step (40) of the receiving bore (15) and is joinedto the valve block (11) by a second swaged connection (41).
 2. Thehydraulic unit of claim 1, in which the valve body (20) has an annulargroove (51), on its outer circumference, for receiving material of thevalve block (11) displaced from a bore step (56) of the receiving bore(15) to make the first swaged connection (31).
 3. The hydraulic unit ofclaim 2, in which an end of the sleeve (19) is beaded into the annulargroove (51).
 4. The hydraulic unit of claim 2, in which the annulargroove (51) is triangular in cross section, and a terminal portion (52)of the sleeve (19) is pressed against one wall (53) of this groove,along an entire circumference of the groove, by crimping.
 5. Thehydraulic unit of claim 4, in which before the first swaged connection(31) is made, the crimped-in portion (52) of the sleeve (19) in theannular groove (51) engages a stop formed by an encompassing edge (55)of the receiving bore (15), the stop limits the insertion depth of thehydraulic part (13) into the valve block (11).
 6. The hydraulic unit ofclaim 2, in which the valve body (20), which is surrounded over only aportion of its length by the sleeve (19), has a diameter-reducingshoulder (59) in a portion free of the sleeve, and that the annulargroove (51) is located in the region of the shoulder (59).
 7. Thehydraulic unit of claim 6, in which the larger-diameter wall (53),toward the sleeve, of the annular groove (51), before the first swagedconnection (31) is made, engages a stop formed by an encompassing edge(55) of the receiving bore (15), the stop limiting the insertion depthof the hydraulic part (13) into the valve block (11).
 8. The hydraulicunit of claim 6, in which the valve body (20), between the annulargroove,(51) and the sleeve (19), has an encompassing shoulder (60) thatincreases its diameter to the outer diameter of the sleeve (19).